Gemstone



FIG. 1 is a front lower right side perspective view of a gemstone having the design;

FIG. 2 is a front plan view thereof;

FIG. 3 is a right side elevation view, the left side elevation view being a mirror image thereof;

FIG. 4 is a rear plan view thereof;

FIG. 5 is a top end elevation view thereof; and,

FIG. 6 is a bottom end elevation view thereof. 

The ornamental design for a gemstone, as shown and described. 